1. Field of the Invention
This invention generally relates to a damper disk assembly. More specifically, the present invention relates to a damper disk assembly for dampening torsional vibrations in a power transmission system.
2. Background Information
A damper disk assembly is often used in a clutch disk assembly of an automobile. The damper disk assembly is formed of an input member, an output member and a damper mechanism. The input member can be coupled to a flywheel. The output member can be coupled to a shaft extending from a transmission. The damper mechanism elastically couples the input and output members together in a rotating direction. The input member is typically formed of a pair of friction facings and a pair of input plates, which are arranged radially inside the friction facings. The friction facings are fixedly coupled to one of the input plates. The output member is typically in the form of a hub that is non-rotatably coupled to the shaft of the transmission. The hub has a centrally located boss with a splined bore, and a radial flange extending outwardly from the boss. The splined bore of the boss is spline-engaged with the shaft of the transmission. The radial flange extends from the boss and is elastically coupled to the input plates by the damper mechanism. The damper mechanism is formed of springs that elastically couple the pair of input plates to the flange of the hub in the rotating direction, and a friction generating mechanism for generating friction between the pair of input plates and the flange.
The flange of the hub is provided with windows (spring accommodating apertures) for receiving the springs therein. The paired input plates are provided with spring support portions (spring accommodating portions) for supporting the springs. Each window supports the circumferentially opposite ends and radially opposite ends of the spring. The spring support portions support the circumferentially opposite ends, radially opposite ends and axially opposite ends of the spring. When the input plate pair rotates relatively to the flange, each spring is compressed between one end surface on one circumferential side of the window and one end surface on the other circumferential side of the spring support portions. In this compressing operation, each of the end surfaces on circumferential opposite sides of the window and the spring support portions move such that the radially outer portions of these surfaces move a distance that is circumferentially longer than the radially inner portions of these surfaces. Therefore, each spring has such a form that the radially outer portion (i.e., the outer portion in the radial direction of the disk) has a circumferential length or width shorter than that of the radially inner portion. When the spring is compressed in a nonparallel fashion as described above, the spring is subjected to a bending force in addition to a shearing force, resulting in a reduced lifetime. When the pair of input plates rotates relatively to the hub, the springs are compressed in the rotating direction so that sliding occurs in the friction generating mechanism. As a result, torsional vibrations in the rotating direction are absorbed and dampened.
According to this clutch disk assembly, when the friction facing is pressed against the flywheel to engage the clutch, a torque is supplied from a flywheel to the input plate pair via the friction facing. The torque is transmitted via the springs to the hub, and then is transmitted to the shaft extending from the transmission. When torsional vibrations occur in the clutch disk assembly, the springs are compressed in the rotating direction, and the input plate pair rotates relatively to the hub. Thereby, sliding occurs in the friction generating mechanism. As a result, the torsional vibrations in the rotating direction are dampened.
In this clutch disk assembly, the flange of the hub is provided with spring accommodating openings for accommodating the springs, and the paired input plates are provided with spring accommodating portions for holding the springs. The spring accommodating opening supports the circumferentially opposite ends and radially opposite ends of the spring, and the spring accommodating portion supports the circumferentially opposite ends, radially opposite ends and axially opposite ends of the spring. A pair of spring seats are arranged on the circumferentially opposite ends of the spring for parallel compression of the spring.
The spring seat has a support portion which extends axially for supporting one of the circumferentially opposite ends of the coil spring, and a projection which extended circumferentially toward the spring from the support portion, and is located within the spring.
Since the spring accommodating portions in the pair of input plates are formed by stamping, the spring seat is supported by stamped edges of the input plates. According to this structure, the spring seat is in contact with the support portions of the paired input plates through a small area so that a surface pressure between them is large, and therefore wearing of the spring seat is liable to occur.
In view of the above, there exists a need for a damper disk assembly which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
An object of the invention is to provide a damper disk assembly that suppresses wearing and breakage of the spring seat in the clutch operation.
A damper disk assembly according to a first aspect of the present invention includes a first rotary member, a pair of second rotary members, a spring member and a pair of spring seats.
The first rotary member is a plate member provided with a spring accommodating opening. The paired second rotary members are disposed on the axially opposite sides of the first rotary member, are fixed together with a predetermined axial space therebetween, and are provided with spring accommodating portions located in the position corresponding to the spring accommodating opening. The spring member is disposed in the spring accommodating opening and the spring accommodating portions for transmitting a torque between the first rotary member and the second rotary member pair. The paired spring seats have support portions extending in the axial direction, supporting the circumferentially opposite ends of the spring member, and being supported by the circumferentially opposite ends of the spring accommodating opening and the spring accommodating portions. The spring accommodating portion is provided at each of its circumferentially opposite ends with a first surface extending in the axial direction, and having an axial length longer than the axial thickness of the second rotary member for contact with the support portion of the spring seat.
In this damper disk assembly, when the torque is supplied to the second rotary member pair, the torque is transmitted to the first rotary member via the spring seat pair and the spring member. When torsional vibrations occur to cause relative rotation between the second rotary member pair and the first rotary member, the spring member is compressed in the rotating direction. In this operation, one of the paired spring seats is pressed to the edge of the spring accommodating opening in the first rotary member, and the other is pressed to the spring support portion of the second rotary member so that the paired spring seats move toward each other.
In this structure, since the spring support portion can be in contact with the support portion of the spring seat through the first surface having a larger area than a contact area in the prior art, the surface pressure applied from the second rotary member pair to the spring seat can be small. Therefore, it is possible to suppress wearing and breakage of the spring seats during rotation of the clutch disk assembly.
According to a second aspect of the present invention, the damper disk assembly of the first aspect of the present invention further has such a feature that the spring accommodating portion is provided at its circumferentially opposite ends with second surfaces for restricting axial movement of the spring seats, respectively.
In this damper disk assembly, the second surfaces of the spring accommodating portion restrict the axial movement of the support portions of the spring seats. Therefore, it is possible to prevent rattling of the spring seats during rotation of the damper disk assembly.
According to a third aspect of the present invention, a damper disk assembly includes a first rotary member, a pair of second rotary members, a spring member and a pair of spring seats. The first rotary member is a plate member provided with a spring accommodating opening. The paired second rotary members are disposed on the axially opposite sides of the first rotary member, are fixed together with a predetermined axial space therebetween, and are provided with spring accommodating portions located in the position corresponding to the spring accommodating opening. The spring member is disposed in the spring accommodating opening and the spring accommodating portions for transmitting a torque between the first rotary member and the second rotary member pair. The paired spring seats have support portions extending in the axial direction, supporting the circumferentially opposite ends of the spring member, and being supported by the circumferentially opposite ends of the spring accommodating opening and the spring accommodating portions. The spring accommodating portion is provided at each of its circumferentially opposite ends with a first wall shaped by drawing into an axially extending form, and supporting a circumferentially outer side and radially opposite sides of the support portion of the spring seat.
In this aspect of the present invention, since the first wall can be in contact with the support portion of the spring seat through a larger area than the conventional structure, a surface pressure applied from the second rotary member pair to the spring seat is small. Therefore, it is possible to prevent wearing and breakage of the spring seat during rotation of the clutch disk assembly.
According to a fourth aspect of the present invention, the damper disk of the third aspect of the present invention further has such a feature that the spring accommodating portion is provided at its circumferentially opposite ends with second walls each formed axially outside the first wall for supporting the axially outer side of the support portion of the spring seat.
In this damper disk assembly, since the second wall restricts the axial movement of the support portion of the spring seat, rattling of the spring seat can be suppressed during rotation of the damper disk assembly.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.